This distro uses the openmosix kernel, and I have found it to be an excellent introduction into the world of HPC clustering otherwise known as Parallel Computing or processing. It has a cluster setup process that is top notch, and perfect for newbies like myself, it will walk you through every step and allow you to get a cluster setup in about 5 minutes just as the site says it will.

http://idea.uab.es/mcreel/ParallelKnoppix/